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eb67868e MD |
1 | /* |
2 | * objstack.c | |
3 | * | |
4 | * Common Trace Format Object Stack. | |
5 | * | |
6 | * Copyright 2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
7 | * | |
8 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
9 | * of this software and associated documentation files (the "Software"), to deal | |
10 | * in the Software without restriction, including without limitation the rights | |
11 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
12 | * copies of the Software, and to permit persons to whom the Software is | |
13 | * furnished to do so, subject to the following conditions: | |
14 | * | |
15 | * The above copyright notice and this permission notice shall be included in | |
16 | * all copies or substantial portions of the Software. | |
17 | * | |
18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
20 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
21 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
22 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
23 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
24 | * SOFTWARE. | |
25 | */ | |
26 | ||
27 | #include <stdlib.h> | |
28 | #include <babeltrace/list.h> | |
29 | #include <babeltrace/babeltrace-internal.h> | |
30 | ||
31 | #define OBJSTACK_INIT_LEN 128 | |
32 | #define OBJSTACK_POISON 0xcc | |
33 | ||
34 | struct objstack { | |
35 | struct bt_list_head head; /* list of struct objstack_node */ | |
36 | }; | |
37 | ||
38 | struct objstack_node { | |
39 | struct bt_list_head node; | |
40 | size_t len; | |
41 | size_t used_len; | |
42 | char data[]; | |
43 | }; | |
44 | ||
45 | BT_HIDDEN | |
46 | struct objstack *objstack_create(void) | |
47 | { | |
48 | struct objstack *objstack; | |
49 | struct objstack_node *node; | |
50 | ||
51 | objstack = calloc(1, sizeof(*objstack)); | |
52 | if (!objstack) | |
53 | return NULL; | |
54 | node = calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN, | |
55 | sizeof(char)); | |
56 | if (!node) { | |
57 | free(objstack); | |
58 | return NULL; | |
59 | } | |
60 | BT_INIT_LIST_HEAD(&objstack->head); | |
61 | bt_list_add_tail(&node->node, &objstack->head); | |
62 | node->len = OBJSTACK_INIT_LEN; | |
63 | return objstack; | |
64 | } | |
65 | ||
66 | static | |
67 | void objstack_node_free(struct objstack_node *node) | |
68 | { | |
69 | size_t offset, len; | |
70 | char *p; | |
71 | ||
72 | if (!node) | |
73 | return; | |
74 | p = (char *) node; | |
75 | len = sizeof(*node) + node->len; | |
76 | for (offset = 0; offset < len; offset++) | |
77 | p[offset] = OBJSTACK_POISON; | |
78 | free(node); | |
79 | } | |
80 | ||
81 | BT_HIDDEN | |
82 | void objstack_destroy(struct objstack *objstack) | |
83 | { | |
84 | struct objstack_node *node, *p; | |
85 | ||
86 | if (!objstack) | |
87 | return; | |
88 | bt_list_for_each_entry_safe(node, p, &objstack->head, node) { | |
89 | bt_list_del(&node->node); | |
90 | objstack_node_free(node); | |
91 | } | |
92 | free(objstack); | |
93 | } | |
94 | ||
95 | static | |
96 | struct objstack_node *objstack_append_node(struct objstack *objstack) | |
97 | { | |
98 | struct objstack_node *last_node, *new_node; | |
99 | ||
100 | /* Get last node */ | |
101 | last_node = bt_list_entry(objstack->head.prev, | |
102 | struct objstack_node, node); | |
103 | ||
104 | /* Allocate new node with double of size of last node */ | |
105 | new_node = calloc(sizeof(struct objstack_node) + (last_node->len << 1), | |
106 | sizeof(char)); | |
107 | if (!new_node) { | |
108 | return NULL; | |
109 | } | |
110 | bt_list_add_tail(&new_node->node, &objstack->head); | |
111 | new_node->len = last_node->len << 1; | |
112 | return new_node; | |
113 | } | |
114 | ||
115 | BT_HIDDEN | |
116 | void *objstack_alloc(struct objstack *objstack, size_t len) | |
117 | { | |
118 | struct objstack_node *last_node; | |
119 | void *p; | |
120 | ||
121 | /* Get last node */ | |
122 | last_node = bt_list_entry(objstack->head.prev, | |
123 | struct objstack_node, node); | |
124 | while (last_node->len - last_node->used_len < len) { | |
125 | last_node = objstack_append_node(objstack); | |
126 | if (!last_node) { | |
127 | return NULL; | |
128 | } | |
129 | } | |
130 | p = &last_node->data[last_node->used_len]; | |
131 | last_node->used_len += len; | |
132 | return p; | |
133 | } |